Cells obtained from patients with various genetic disorders will be utilized in an attempt to (1) precisely define the "optimal" culture conditions for demonstration of the cellular defect; (2) delineate the basic mechanism involved in the production of the cellular defect in culture; (3) determine the bases of metabolic control of enzyme synthesis and regulation of enzyme activity in a specific metabolic disease; (4) investigate genetic-heterogeneity and metabolic cooperation between various mutants in this disorder; (5) relate the cellular defect to the clinical manifestations of the particular disorders; and (6) detect patients and delineate heterozygotes.